Refrigeration cycle device

Abstract

A refrigeration cycle device is a refrigeration cycle device using a non-azeotropic mixed refrigerant, wherein the device comprises: a compressor; a first heat exchanger; a first expansion valve; a second heat exchanger; the second expansion valve is connected to the second heat exchanger via a first flow path; a third expansion valve is communicated with the first flow path; a refrigerant container is communicated with the first expansion valve, the second expansion valve and the third expansion valve; and a control device, wherein the non-azeotropic mixed refrigerant circulates in a first circulation direction of the compressor, the first heat exchanger, the first expansion valve and the second heat exchanger, when the third expansion valve is opened, the non-azeotropic mixed refrigerant in the gas in the refrigerant container is guided to the first flow path, at least a part of the non-azeotropic mixed refrigerant flowing into the refrigerant container from the first expansion valve is vaporized in the refrigerant container, and when a first difference between a second temperature of the non-azeotropic mixed refrigerant in the gas in the refrigerant container and a third temperature of the non-azeotropic mixed refrigerant in the liquid in the refrigerant container is greater than a first threshold value, the control device opens the third expansion valve.

Description

[0001] This application is a divisional application of the invention patent application with application date of June 29, 2018, application number 201880094260.6, and invention name “Refrigeration Cycle Device”. Technical Field

[0002] The present invention relates to a refrigeration cycle device using a non-azeotropic mixed refrigerant. Background Art

[0003] In the past, refrigeration cycle devices using non-azeotropic mixed refrigerants are known. For example, International Publication No. 2015 / 140884 (Patent Document 1) discloses a refrigeration cycle device using a non-azeotropic mixed refrigerant containing a first refrigerant and a second refrigerant, wherein the first refrigerant has the characteristic of producing a disproportionation reaction (self-decomposition reaction), and the second refrigerant has a higher boiling point than the first refrigerant at the same pressure. In this refrigeration cycle device, in the initial state after the compressor is started, compared with normal operation, the temperature or pressure of the refrigerant discharged from the compressor is suppressed based on the amount of liquid refrigerant in the gas-liquid separator, so that the disproportionation reaction of the first refrigerant can be prevented, thereby improving the performance of the refrigeration cycle device.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2015 / 140884 Summary of the invention

[0007] Problems to be solved by the invention

[0008] From the perspective of preventing global warming, non-azeotropic mixed refrigerants, which are refrigerants with lower global warming potential (GWP) values ​​mixed with a single-component refrigerant, are sometimes used in refrigeration cycle devices. In non-azeotropic mixed refrigerants, a temperature gradient sometimes occurs between the temperature of the saturated liquid and the temperature of the saturated vapor at the same pressure. If the temperature gradient increases, the temperature of the non-azeotropic mixed refrigerant flowing into the heat exchanger functioning as an evaporator decreases, and frost is easily generated. As a result, the performance of the refrigeration cycle device may be reduced.

[0009] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to reduce the GWP of a non-azeotropic refrigerant mixture and to suppress a decrease in the performance of a refrigeration cycle device using the non-azeotropic refrigerant mixture.

[0010] Means for solving problems

[0011] A refrigeration cycle device is a refrigeration cycle device using a non-azeotropic mixed refrigerant, wherein the device comprises: a compressor; a first heat exchanger; a first expansion valve; a second heat exchanger; a second expansion valve, the second expansion valve being connected to the second heat exchanger via a first flow path; a third expansion valve, the third expansion valve being communicated with the first flow path; a refrigerant container, the refrigerant container being communicated with the first expansion valve, the second expansion valve, and the third expansion valve; and a control device, wherein the non-azeotropic mixed refrigerant circulates in a first circulation direction of the compressor, the first heat exchanger, the first expansion valve, and the second heat exchanger, when the third expansion valve is opened, the non-azeotropic mixed refrigerant in the gas in the refrigerant container is guided to the first flow path, at least a portion of the non-azeotropic mixed refrigerant flowing into the refrigerant container from the first expansion valve is vaporized in the refrigerant container, and when a first difference between a second temperature of the non-azeotropic mixed refrigerant in the gas in the refrigerant container and a third temperature of the non-azeotropic mixed refrigerant in the liquid in the refrigerant container is greater than a first threshold value, the control device opens the third expansion valve.

[0012] Effects of the Invention

[0013] According to the refrigeration cycle device of the present invention, the first weight ratio of R32 in the non-azeotropic mixed refrigerant in a sealed state in the refrigeration cycle device is less than 43wt%, the second weight ratio of CF3I is less than the first weight ratio, and the third weight ratio of R1123 is more than 14wt%, thereby reducing the GWP of the non-azeotropic mixed refrigerant and suppressing the performance reduction of the refrigeration cycle device using the non-azeotropic mixed refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a functional block diagram showing the configuration of the refrigeration cycle device according to Embodiment 1.

[0015] Figure 2 This is a Ph diagram showing the relationship between enthalpy, pressure and temperature of a general non-azeotropic refrigerant mixture.

[0016] Figure 3 This is a graph showing the relationship between the ratio of the weight ratio of R32 to the weight ratio of CF3I and the temperature gradient.

[0017] Figure 4 Is used to illustrate the Figure 1 Flow chart of the process of reducing the exhaust temperature performed by the control device.

[0018] Figure 5 This is a functional block diagram showing the configuration of a refrigeration cycle device according to Modification 1 of Embodiment 1.

[0019] Figure 6This is a functional block diagram showing the configuration of a refrigeration cycle device according to Modification 2 of Embodiment 1.

[0020] Figure 7 These are simulation results when the weight ratio of R32 in the non-azeotropic mixed refrigerant is set to 43 wt % and the weight ratio of R1123 is changed within a range of 14 wt % to less than 57 wt %.

[0021] Figure 8 These are simulation results when the weight ratio of R32 in the non-azeotropic mixed refrigerant is set to 30 wt % and the weight ratio of R1123 is changed within a range of 40 wt % to less than 70 wt %.

[0022] Fig. 9 This is a functional block diagram showing the configuration of the refrigeration cycle device according to Embodiment 2 together with the flow of the refrigerant during cooling operation.

[0023] Fig.10 This is a Ph diagram showing the change in the state of the non-azeotropic refrigerant mixture during cooling operation.

[0024] Fig.11 This is a functional block diagram showing the configuration of the refrigeration cycle device according to Embodiment 2 together with the flow of the refrigerant during the heating operation.

[0025] Fig.12 This is a Ph diagram showing the change in the state of the non-azeotropic refrigerant mixture during the heating operation.

[0026] Fig.13 Is used to illustrate the Fig. 9 as well as Fig.11 FIG. 1 is an example of a flowchart of control of the third expansion valve by the control device.

[0027] Fig.14 Is used to illustrate the Fig. 9 and Fig.11 Another example of a flowchart of control of the third expansion valve by the control device.

[0028] Fig.15 This is a functional block diagram showing the structure of a refrigeration cycle device according to Modification 1 of Embodiment 2.

[0029] Fig.16 This is a functional block diagram showing the structure of a refrigeration cycle device according to a second modification of the second embodiment.

[0030] Fig.17 This is a Ph diagram showing the change in the state of the non-azeotropic refrigerant mixture during cooling operation.

[0031] Fig.18This is a Ph diagram showing the change in the state of the non-azeotropic refrigerant mixture during the heating operation.

[0032] Fig.19 Is used to illustrate the Fig.16 Flowchart of control of the third expansion valve by the control device.

[0033] Fig. 20 This is a functional block diagram showing the structure of a refrigeration cycle device according to a third modification of the second embodiment.

[0034] Fig.21 This is a functional block diagram showing the structure of a refrigeration cycle device according to a fourth modification of the second embodiment. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals are given to the same or corresponding parts in the drawings, and their description will not be repeated in principle.

[0036] Implementation method 1.

[0037] Figure 1 1 is a functional block diagram showing the structure of the refrigeration cycle device 100 according to Embodiment 1. As the refrigeration cycle device 100, for example, a PAC (Package Air Conditioner) can be cited. Figure 1 As shown, the refrigeration cycle device 100 includes an outdoor unit 110 and an indoor unit 120. The outdoor unit 110 includes: a compressor 1; a four-way valve 2 (flow path switching valve); an expansion valve 4A (a first expansion valve); an expansion valve 4B (a second expansion valve); a storage tank 5 (a refrigerant container); a heat exchanger 6 (a first heat exchanger); an outdoor fan 11; a control device 10; and a temperature sensor 13. The indoor unit 120 includes: a heat exchanger 3 (a second heat exchanger); and an indoor fan 12.

[0038] In the refrigeration cycle device 100, a non-azeotropic mixed refrigerant whose GWP is reduced by mixing R32, CF3I and R1123 is used. The weight ratio of R32 in the non-azeotropic mixed refrigerant in a sealed state in the refrigeration cycle device 100 is 43wt% or less. The weight ratio of CF3I in the non-azeotropic mixed refrigerant in a sealed state in the refrigeration cycle device 100 is less than the weight ratio of R32. The weight ratio of R1123 in the non-azeotropic mixed refrigerant in a sealed state in the refrigeration cycle device 100 is 14wt% or more. Even in the case where the number of units shipped of the refrigeration cycle device 100 increases and the amount of non-azeotropic mixed refrigerant used increases, in order to meet restrictions related to refrigerants (such as the Monte Triol Protocol or F-gas restrictions), it is preferred that the weight ratio of R32 is set to 30wt% or less to further reduce the GWP.

[0039] The boiling points of R32, CF3I and R1123 are -52°C, -22.5°C and -56°C, respectively. R1123 increases the operating pressure of the non-azeotropic refrigerant mixture. By including R1123 in the non-azeotropic refrigerant mixture, the volume (stroke volume) of the compressor 1 required to ensure the desired operating pressure can be reduced, so the compressor 1 can be miniaturized. In addition, the non-azeotropic refrigerant mixture may also contain refrigerants other than R32, CF3I and R1123 (for example, R1234yf, R1234ze (E), R290 or CO2) within the range that does not hinder the reduction of GWP.

[0040] The control device 10 controls the amount of refrigerant discharged per unit time by the compressor 1 by controlling the driving frequency of the compressor 1 so that the temperature in the indoor unit 120 obtained by the temperature sensor not shown becomes a desired temperature (for example, a temperature set by the user). The control device 10 controls the opening of the expansion valves 4A and 4B so that the superheat or subcooling of the non-azeotropic refrigerant mixture becomes a value within a desired range. The control device 10 controls the air supply volume per unit time of the outdoor fan 11 and the indoor fan 12. The control device 10 obtains the discharge temperature Td (first temperature) of the non-azeotropic refrigerant mixture discharged from the compressor 1 from the temperature sensor 13. The control device 10 controls the four-way valve 2 to switch the circulation direction of the non-azeotropic refrigerant mixture.

[0041] The control device 10 controls the four-way valve 2 to communicate the discharge port of the compressor 1 with the heat exchanger 6 and communicate the heat exchanger 3 with the suction port of the compressor 1 during the refrigeration operation. During the refrigeration operation, the non-azeotropic mixed refrigerant circulates in order through the compressor 1, the four-way valve 2, the heat exchanger 6, the expansion valve 4A, the accumulator 5, the expansion valve 4B, the heat exchanger 3, the four-way valve 2, and the accumulator 5. A portion of the non-azeotropic mixed refrigerant flowing from the expansion valve 4A into the accumulator 5 is separated into a liquid non-azeotropic mixed refrigerant and a gaseous non-azeotropic mixed refrigerant and stored in the accumulator 5.

[0042] The control device 10 controls the four-way valve 2 to communicate the discharge port of the compressor 1 with the heat exchanger 3 and communicate the heat exchanger 6 with the suction port of the compressor 1 during the heating operation. During the heating operation, the non-azeotropic mixed refrigerant circulates in order through the compressor 1, the four-way valve 2, the heat exchanger 3, the expansion valve 4B, the accumulator 5, the expansion valve 4A, the heat exchanger 6, the four-way valve 2, and the accumulator 5. A portion of the non-azeotropic mixed refrigerant flowing from the expansion valve 4B into the accumulator 5 is separated into a liquid non-azeotropic mixed refrigerant and a gaseous non-azeotropic mixed refrigerant and stored in the accumulator 5.

[0043] Figure 2 This is a Ph diagram showing the relationship between enthalpy, pressure and temperature of a general non-azeotropic refrigerant mixture. Figure 2In the diagram, the curves LC and GC represent the saturated liquid line and the saturated vapor line, respectively. The saturated liquid line and the saturated vapor line are connected at the critical point CP. The points LP and GP on the saturated liquid line LC represent the points on the saturated liquid line and the saturated vapor line, respectively, at the pressure P1. Figure 2 Isotherms of temperatures T1 and T2 (< T1) are shown in FIG.

[0044] like Figure 2 As shown in FIG. 1 , a temperature gradient of T1-T2 is generated between points GP and LP. The non-azeotropic refrigerant mixture sometimes has the following characteristics: in the gas-liquid two-phase state (the region between the saturated liquid line LC and the saturated vapor line GC) at the same pressure, the lower the enthalpy, the lower the temperature. The larger the temperature gradient, the lower the temperature of the non-azeotropic refrigerant mixture flowing into the heat exchanger 6 functioning as an evaporator during the heating operation, and frost is likely to form in the heat exchanger 6. As a result, the performance of the refrigeration cycle device 100 may be reduced.

[0045] Therefore, in the refrigeration cycle device 100, the temperature gradient is suppressed by setting the weight ratio of CF3I in the non-azeotropic refrigerant mixture in a sealed state in the refrigeration cycle device 100 to be less than the weight ratio of R32.

[0046] Figure 3 : is a graph showing the relationship between the weight ratio of R32 to the weight ratio of CF3I and the temperature gradient. Figure 3 As shown, by setting the weight ratio of CF3I to be less than or equal to the weight ratio of R32 (the ratio of the weight ratio of R32 to the weight ratio of CF3I is 1.0 or more), the temperature gradient can be suppressed.

[0047] It is known that CF3I contained in the non-azeotropic mixed refrigerant used in the refrigeration cycle device 100 will fluorinate or iodinate in a high temperature environment (for example, about 100°C). If CF3I is fluorinated or iodinated, impurities (sludge) will be generated in the refrigeration cycle device 100 due to metal corrosion of the piping, and the possibility of failure of the refrigeration cycle device 100 will increase. Therefore, in the refrigeration cycle device 100, in order to prevent fluorination and iodination of CF3I, when the discharge temperature Td of the non-azeotropic mixed refrigerant discharged from the compressor 1 is above the reference temperature (for example, 100°C), control is performed to reduce the discharge temperature Td. As a result, the safety of the refrigeration cycle device 100 can be improved.

[0048] Figure 4 Is used to illustrate the Figure 1 The flow chart of the process of lowering the discharge temperature Td performed by the control device 10 of the refrigeration cycle device 10 is shown. The main routine (not shown) for performing the overall control of the refrigeration cycle device 100 is called at regular time intervals. Figure 4 In addition, only step S is recorded below.

[0049] like Figure 4 As shown, in S101, the control device 10 determines whether the discharge temperature Td is less than the reference temperature τ1. When the discharge temperature Td is less than the reference temperature τ1 (Yes in S101), the control device 10 returns the process to the main routine. When the discharge temperature Td is greater than the reference temperature τ1 (No in S101), the control device 10 advances the process to S102.

[0050] In S102, the control device 10 reduces the driving frequency of the compressor 1 and causes the process to proceed to S103. In S103, the control device 10 increases the air supply to the heat exchanger, which functions as a condenser, and causes the process to proceed to S104. In cooling operation, in S103, the control device 10 increases the air supply per unit time of the outdoor fan 11. In heating operation, in S103, the control device 10 increases the air supply of the indoor fan 12. In S104, the control device 10 increases the opening of the expansion valves 4A and 4B and causes the process to return to the main routine.

[0051] In addition, it is sufficient to perform at least one of S102 to S104, and it is not necessary to perform all of S102 to S104. Figure 4 Proceed in the order shown.

[0052] In the first embodiment, a refrigeration cycle device including a refrigerant container storing a non-azeotropic mixed refrigerant is described. The refrigeration cycle device of the first embodiment may also be, for example, Figure 5 The refrigeration cycle device 100A of the modification 1 of the embodiment 1 shown in FIG. 1 does not include a refrigerant container. The refrigeration cycle device 100A is configured such that Figure 1 The refrigeration cycle device 100 is configured such that the accumulator 5 is removed and the expansion valves 4A and 4B are replaced by the expansion valve 4 (first expansion valve). As the refrigeration cycle device 100A, for example, a RAC (Room Air Conditioner) can be cited.

[0053] In the first embodiment and the first modification, the case where the circulation direction of the refrigerant is switched by the flow path switching valve is described. Figure 6 The flow path switching valve is not provided like the refrigeration cycle device 100B of the modification 2 of the illustrated embodiment 1. As the refrigeration cycle device 100B, for example, a refrigerator or a display freezer can be given.

[0054] In Embodiment 1 and Modification 1, a refrigeration cycle apparatus including one outdoor unit and one indoor unit is described. The refrigeration cycle apparatus of the embodiment may include a plurality of outdoor units, or may include a plurality of indoor units.

[0055] As described above, according to the refrigeration cycle device of embodiment 1 and variants 1 and 2, the GWP of the non-azeotropic refrigerant mixture can be reduced, and the performance reduction of the refrigeration cycle device using the non-azeotropic refrigerant mixture can be suppressed. In addition, according to the refrigeration cycle device of embodiment 1 and variants 1 and 2, the safety of the refrigeration cycle device 100 can be improved.

[0056] Implementation method 2.

[0057] In Embodiment 1, a refrigeration cycle device using a non-azeotropic mixed refrigerant containing R32, CF3I, and R1123 is described. R1123, which has the lowest boiling point among R32, CF3I, and R1123, is easily vaporized, so as the refrigeration cycle device continues to operate, the weight ratio of R1123 contained in the refrigerant container increases. As a result, the weight ratio of R1123 in the non-azeotropic mixed refrigerant (circulating refrigerant) circulating in the refrigeration cycle device decreases.

[0058] Figure 7 as well as Figure 8 The figures show (a) the simulation results of the relationship between the weight ratio of R1123 in the non-azeotropic mixed refrigerant and the temperature gradient, and (b) the simulation results of the relationship between the weight ratio and the pressure loss ratio. Figure 7 These are simulation results when the weight ratio of R32 in the non-azeotropic mixed refrigerant is set to 43 wt % and the weight ratio of R1123 is changed within a range of 14 wt % to less than 57 wt %. Figure 8 It is the simulation result when the weight ratio of R32 in the non-azeotropic refrigerant mixture is set to 30wt% and the weight ratio of R1123 is changed within the range of 40wt% or more and less than 70wt%. In addition, the pressure loss ratio is the ratio of the pressure loss when the weight ratio of R1123 is a certain value to the pressure loss when the weight ratio of R1123 is the minimum.

[0059] like Figure 7 (a) and Figure 8 As shown in (a), the temperature gradient decreases as the weight ratio of R1123 increases. Figure 7 (b) and Figure 8 As shown in (b), the pressure loss ratio decreases as the weight ratio of R1123 increases.

[0060] Therefore, in Embodiment 2, when the temperature gradient exceeds the threshold value, the increase in the temperature gradient and the increase in the pressure loss ratio are suppressed by returning the R1123 in the refrigerant container to the circulating refrigerant. As a result, the performance reduction of the refrigeration cycle device caused by the reduction in the weight ratio of R1123 in the circulating refrigerant can be suppressed.

[0061] Fig. 9 2 is a functional block diagram showing the structure of the refrigeration cycle device 200 according to Embodiment 2 and the flow of the refrigerant during the cooling operation. Figure 1 The outdoor unit 110 of the refrigeration cycle device 100 is replaced with the outdoor unit 210. The structure of the outdoor unit 210 is Figure 1 The expansion valve 4C (third expansion valve), the three-way valve 8 (flow path switching unit), the internal heat exchanger 7 (third heat exchanger) and the temperature sensors 9A to 9C are added to the structure of the outdoor unit 110, and Figure 1 The control device 10 is replaced by the control device 20. Other than that, the configuration is the same and therefore the description will not be repeated.

[0062] like Fig. 9 As shown, the internal heat exchanger 7 is connected between the accumulator 5 and the expansion valve 4C, and is connected between the four-way valve 2 and the accumulator 5. The three-way valve 8 is connected between the expansion valve 4C and the flow path FP1 (first flow path), and the flow path FP1 connects the heat exchanger 3 and the expansion valve 4B. In addition, the three-way valve 8 is connected between the expansion valve 4C and the flow path FP2 (second flow path), and the flow path FP2 connects the expansion valve 4A and the heat exchanger 6. The refrigeration operation of the refrigeration cycle device 200 starts in a state where the expansion valve 4C is closed. In addition, the connection position of the internal heat exchanger 7 can be any connection position as long as it is a connection position for the non-azeotropic mixed refrigerant flowing between the four-way valve 2 and the suction port of the compressor 1 to pass. For example, it can also be connected between the accumulator 5 and the expansion valve 4C, and connected between the accumulator 5 and the suction port of the compressor 1.

[0063] The control device 20 controls the amount of refrigerant discharged per unit time by the compressor 1 by controlling the driving frequency of the compressor 1 so that the temperature in the indoor unit 120 becomes a desired temperature. The control device 20 controls the opening of the expansion valves 4A and 4B so that the superheat or subcooling of the non-azeotropic mixed refrigerant becomes a value within a desired range. The control device 20 controls the air supply volume per unit time of the outdoor fan 11 and the indoor fan 12.

[0064] The control device 20 obtains the discharge temperature Td (first temperature) of the non-azeotropic mixed refrigerant discharged from the compressor 1 from the temperature sensor 13. The control device 20 obtains the temperature T91 (second temperature) of the non-azeotropic mixed refrigerant of the gas in the accumulator 5 from the temperature sensor 9A. The control device 20 obtains the temperature T92 (third temperature) of the non-azeotropic mixed refrigerant of the liquid in the accumulator 5 from the temperature sensor 9B. The control device 20 obtains the temperature T93 (fourth temperature) of the non-azeotropic mixed refrigerant flowing between the internal heat exchanger 7 and the expansion valve 4C from the temperature sensor 9C.

[0065] In addition, Fig. 9 , the temperature sensors 9A and 9B are provided on the side of the storage tank 5, but the positions where the temperature sensors 9A and 9B are provided are not limited to the side of the storage tank 5. The temperature sensor 9A may be provided at any position as long as the temperature of the non-azeotropic mixed refrigerant of the gas in the storage tank 5 can be measured, for example, it may be provided at the top or upper surface of the storage tank 5. In addition, the temperature sensor 9B may be provided at any position as long as the temperature of the non-azeotropic mixed refrigerant of the liquid in the storage tank 5 can be measured, for example, it may be provided at the bottom or bottom surface of the storage tank 5.

[0066] In cooling operation, the controller 20 controls the four-way valve 2 to connect the discharge port of the compressor 1 to the heat exchanger 6 and connect the heat exchanger 3 to the internal heat exchanger 7. The controller 20 controls the three-way valve 8 to connect the expansion valve 4C to the flow path FP1.

[0067] In the cooling operation, the non-azeotropic mixed refrigerant circulates in order through the compressor 1, the four-way valve 2, the heat exchanger 6, the expansion valve 4A, the accumulator 5, the expansion valve 4B, the heat exchanger 3, the four-way valve 2, the internal heat exchanger 7, and the accumulator 5. A part of the non-azeotropic mixed refrigerant flowing from the expansion valve 4A into the accumulator 5 is separated into liquid non-azeotropic mixed refrigerant and gas non-azeotropic mixed refrigerant, and stored in the accumulator 5. When the expansion valve 4C is open, the gas non-azeotropic mixed refrigerant in the accumulator 5 is guided to the flow path FP1.

[0068] The node N1 is a node through which the non-azeotropic mixed refrigerant flowing between the compressor 1 and the four-way valve 2 passes. The node N2 is a node through which the non-azeotropic mixed refrigerant flowing between the heat exchanger 6 and the expansion valve 4A passes. The three-way valve 8 and the flow path FP2 are connected to the three-way valve 8 at the node N2. The node N3 is a node through which the non-azeotropic mixed refrigerant flowing between the expansion valve 4A and the accumulator 5 passes.

[0069] Node N4 is a node through which the non-azeotropic mixed refrigerant flowing between the accumulator 5 and the expansion valve 4B passes. Node N5 is a node through which the non-azeotropic mixed refrigerant flowing between the expansion valve 4B and the heat exchanger 3 passes. Flow path FP1 is connected to the three-way valve 8 at node N5. Node N6 is a node through which the non-azeotropic mixed refrigerant flowing between the four-way valve 2 and the internal heat exchanger 7 passes. Node N7 is a node through which the non-azeotropic mixed refrigerant flowing between the internal heat exchanger 7 and the accumulator 5 passes. Node N8 is a node through which the refrigerant flowing between the accumulator 5 and the compressor 1 passes.

[0070] The node N9 is a node through which the non-azeotropic mixed refrigerant flowing between the storage 5 and the internal heat exchanger 7 passes. The node N10 is a node through which the non-azeotropic mixed refrigerant flowing between the internal heat exchanger 7 and the expansion valve 4C passes. The node N11 is a node through which the non-azeotropic mixed refrigerant flowing between the three-way valve 8 and the flow path FP1 passes. The node N12 is a node through which the non-azeotropic mixed refrigerant flowing between the three-way valve 8 and the flow path FP2 passes.

[0071] Fig.10 This is a Ph diagram showing the change in the state of the non-azeotropic refrigerant mixture during cooling operation. Fig.10 The states shown correspond to Fig. 9 The states of the non-azeotropic mixed refrigerant in the nodes N1 to N11 are shown in FIG. State C1 represents the state of the non-azeotropic mixed refrigerant flowing between the expansion valve 4B and the node N5.

[0072] Refer to Fig. 9 as well as Fig.10 The process from the state of node N8 to the state of node N1 represents the adiabatic compression process by the compressor 1. The temperature of the non-azeotropic mixed refrigerant at the state of node N1 is measured by the temperature sensor 13 as the discharge temperature Td. The process from the state of node N1 to the state of node N2 represents the condensation process by the heat exchanger 6. The process from the state of node N2 to the state of node N3 represents the decompression process by the expansion valve 4A. The state of node N4 is the state of the saturated liquid flowing out of the storage 5. Fig.10 The temperature sensor 9B measures the temperature of the non-azeotropic mixed refrigerant at the state of the node N4 as the temperature T92. The process from the state of the node N4 to the state C1 represents the decompression process by the expansion valve 4B.

[0073] The state of the node N9 is the state of the saturated vapor flowing out of the storage 5. Fig.10Indicated on the saturated vapor line. The temperature of the non-azeotropic mixed refrigerant in the state of node N9 is measured by the temperature sensor 9A as temperature T91 (>T92). The process from the state of node N9 to the state of node N10 represents the cooling process based on the internal heat exchanger 7. The temperature of the non-azeotropic mixed refrigerant in the state of node N10 is measured by the temperature sensor 9C as temperature T93 (<T92). The process from the state of node N10 to the state of node N11 represents the decompression process based on the expansion valve 4C. The enthalpy of the state of node N11 is smaller than the enthalpy of state C1. Therefore, the enthalpy of the state of node N5 is larger than the enthalpy of node N11 and smaller than the enthalpy of state C1, and the node N5 is the node where the non-azeotropic mixed refrigerant in the state of node N11 merges with the non-azeotropic mixed refrigerant in the state C1.

[0074] The process from the state of the node N5 to the state of the node N6 represents the evaporation process based on the heat exchanger 3. In the process from the state of the node N6 to the state of the node N7, the non-azeotropic mixed refrigerant absorbs heat from the non-azeotropic mixed refrigerant in the state of the node N9 through the internal heat exchanger 7. Therefore, the enthalpy of the state of the node N7 is greater than the enthalpy of the state of the node N6.

[0075] In the refrigeration cycle device 100, the enthalpy of the non-azeotropic mixed refrigerant flowing into the heat exchanger 3 functioning as an evaporator during the cooling operation (the enthalpy of the state of the node N5) is reduced compared with the enthalpy of the non-azeotropic mixed refrigerant flowing out of the expansion valve 4B (the enthalpy of the state C1) based on the internal heat exchanger 7. In addition, the enthalpy of the non-azeotropic mixed refrigerant sucked into the compressor 1 (the enthalpy of the state of the node N8) is increased compared with the enthalpy of the non-azeotropic mixed refrigerant flowing out of the heat exchanger 3 (the enthalpy of the state of the node N6) based on the internal heat exchanger 7. Therefore, the difference between the enthalpy of the non-azeotropic mixed refrigerant flowing into the heat exchanger 3 and the enthalpy of the non-azeotropic mixed refrigerant sucked into the compressor 1 increases. As a result, the efficiency of the cooling operation of the refrigeration cycle device 100 can be improved.

[0076] Fig.11 This is a functional block diagram showing the structure of the refrigeration cycle device 200 of Embodiment 2 and the flow of the refrigerant in the heating operation. The heating operation of the refrigeration cycle device 200 is also started in the state where the expansion valve 4C is closed. In the heating operation, the control device 20 connects the discharge port of the compressor 1 with the heat exchanger 3, and connects the heat exchanger 6 with the internal heat exchanger 7. The control device 20 controls the three-way valve 8 to connect the expansion valve 4C with the flow path FP2.

[0077] In the heating operation, the non-azeotropic mixed refrigerant circulates in order through the compressor 1, the four-way valve 2, the heat exchanger 3, the expansion valve 4B, the accumulator 5, the expansion valve 4A, the heat exchanger 6, the four-way valve 2, the internal heat exchanger 7, and the accumulator 5. A part of the non-azeotropic mixed refrigerant flowing from the expansion valve 4B into the accumulator 5 is separated into liquid non-azeotropic mixed refrigerant and gas non-azeotropic mixed refrigerant, and is stored in the accumulator 5.

[0078] Fig.12 This is a Ph diagram showing the change in the state of the non-azeotropic refrigerant mixture during the heating operation. Fig.12 The states shown correspond to Fig.11 The state C2 represents the state of the non-azeotropic refrigerant mixture flowing between the expansion valve 4A and the node N2.

[0079] Refer to Fig.11 and Fig.12 The process from the state of node N8 to the state of node N1 represents the adiabatic compression process based on the compressor 1. The temperature of the non-azeotropic mixed refrigerant at the state of node N1 is measured by the temperature sensor 13 as the discharge temperature Td. The process from the state of node N1 to the state of node N5 represents the condensation process based on the heat exchanger 3. The process from the state of node N5 to the state of node N4 represents the decompression process based on the expansion valve 4B. The state of node N3 is the state of the saturated liquid flowing out of the storage 5. Fig.12 The temperature of the non-azeotropic mixed refrigerant in the state of the node N3 is measured by the temperature sensor 9B as the temperature T92. The process from the state of the node N3 to the state C2 represents the decompression process by the expansion valve 4A.

[0080] The state of the node N9 is the state of the saturated vapor flowing out of the storage 5. Fig.12 Indicated on the saturated vapor line. The temperature of the non-azeotropic mixed refrigerant in the state of node N9 is measured by the temperature sensor 9A as temperature T91 (>T92). The process from the state of node N9 to the state of node N10 represents the cooling process based on the internal heat exchanger 7. The temperature of the non-azeotropic mixed refrigerant in the state of node N10 is measured by the temperature sensor 9C as temperature T93 (<T92). The process from the state of node N10 to node N12 represents the decompression process based on the expansion valve 4C. The enthalpy of the state of node N12 is smaller than the enthalpy of state C2. Therefore, the enthalpy of the state of node N2 is larger than the enthalpy of node N12 and smaller than the enthalpy of state C2, and the node N2 is the node where the non-azeotropic mixed refrigerant in the state of node N12 merges with the non-azeotropic mixed refrigerant in the state C2.

[0081] The process from the state of the node N2 to the state of the node N6 represents an evaporation process based on the heat exchanger 6. In the process from the state of the node N6 to the state of the node N7, the non-azeotropic mixed refrigerant absorbs heat from the non-azeotropic mixed refrigerant in the state of the node N9 in the internal heat exchanger 7. Therefore, the enthalpy of the state of the node N7 is greater than the enthalpy of the state of the node N6.

[0082] In the refrigeration cycle device 100, the enthalpy of the non-azeotropic mixed refrigerant flowing into the heat exchanger 6 functioning as an evaporator during the heating operation (the enthalpy of the state of the node N2) is reduced compared with the enthalpy of the non-azeotropic mixed refrigerant flowing out of the expansion valve 4A (the enthalpy of the state C2) based on the internal heat exchanger 7. In addition, the enthalpy of the non-azeotropic mixed refrigerant sucked into the compressor 1 (the enthalpy of the state of the node N8) is increased compared with the enthalpy of the non-azeotropic mixed refrigerant flowing out of the heat exchanger 6 (the enthalpy of the state of the node N6) based on the internal heat exchanger 7. Therefore, the difference between the enthalpy of the non-azeotropic mixed refrigerant flowing into the heat exchanger 6 and the enthalpy of the non-azeotropic mixed refrigerant sucked into the compressor 1 increases. As a result, the efficiency of the heating operation of the refrigeration cycle device 100 can be improved.

[0083] Fig.13 Is used to illustrate the Fig. 9 as well as Fig.11 An example of a flowchart of the control of the expansion valve 4C by the control device 20. The main routine (not shown) for performing the overall control of the refrigeration cycle device 200 is called at regular time intervals. Fig.13 Processing shown. Fig.13 The processing shown is performed in cooling operation and heating operation.

[0084] like Fig.13 As shown, in S201, the control device 20 determines whether the expansion valve 4C is open. When the expansion valve 4C is closed (No in S201), the control device 20 causes the processing to enter S202. In S202, the control device 20 determines whether the difference (temperature gradient) between the temperatures T91 and T92 is above the threshold value δ1 (first threshold value). When the temperature gradient is less than the threshold value δ1 (No in S202), the control device 20 returns the processing to the main routine. When the temperature gradient is above the threshold value δ1 (Yes in S202), the control device 20 causes the processing to enter S203. In S203, the control device 20 opens the opening of the expansion valve 4C to the reference opening, and returns the processing to the main routine.

[0085] When the expansion valve 4C is open (Yes in S201), the control device 20 causes the process to enter S204. In S204, the control device 20 determines whether the difference between the temperatures T91 and T93 is greater than the threshold value δ2. When the difference between the temperatures T91 and T93 is less than the threshold value δ2 (No in S204), the control device 20 causes the process to enter S205. In S205, the control device 20 reduces the opening of the expansion valve 4C by a certain opening, and then returns the process to the main routine. When the difference between the temperatures T91 and T93 is greater than the threshold value δ2 (Yes in S204), the control device 20 causes the process to enter S206. In S206, the control device 20 increases the opening of the expansion valve 4C by a certain opening, and then returns the process to the main routine.

[0086] Fig.14 Is used to illustrate the Fig. 9 and Fig.11 Another example of a flowchart of the control of the expansion valve 4C by the control device 20. Fig.14 The flowchart shown is in Fig.13 The flowchart shown has S207 and S208 added thereto. S201 to S206 are the same, and therefore description thereof will not be repeated.

[0087] like Fig.14 As shown, after S203, S205 or S206, in S207, the control device 20 determines whether the temperature gradient is greater than the threshold value δ1. When the temperature gradient is less than the threshold value δ1 (No in S207), the control device 20 causes the process to enter S208. In S208, the control device 20 returns the process to the main routine after closing the expansion valve 4C. When the temperature gradient is greater than the threshold value δ1 (Yes in S207), the control device 20 returns the process to the main routine. Fig.14 In the case of the processing shown, it is not necessary to close the expansion valve 4C at the start of the cooling operation and the heating operation.

[0088] In Embodiment 2, a case where a three-way valve is used as a flow path switching unit is described. The flow path switching unit is not limited to a three-way valve, and may be any structure as long as it switches the flow path of the non-azeotropic mixed refrigerant of the gas from the refrigerant container. Fig.15 The refrigeration cycle device 200A of the modification 1 of the second embodiment shown in FIG. 1 includes two on-off valves. The refrigeration cycle device 200A is configured such that Fig. 9 The three-way valve 8 and the control device 20 of the refrigeration cycle device 200 are replaced with the flow path switching unit 80 and the control device 20A, respectively. The other structures are the same, so the description will not be repeated.

[0089] like Fig.15As shown, the flow path switching unit 80 includes on-off valves 8A and 8B. The on-off valve 8A is connected between the expansion valve 4C and the node N5. The on-off valve 8B is connected between the expansion valve 4C and the node N2. In cooling operation, the control device 20A opens the on-off valve 8A and closes the on-off valve 8B. In heating operation, the control device 20A closes the on-off valve 8A and opens the on-off valve 8B.

[0090] In Embodiment 2, a refrigeration cycle device having a third heat exchanger is described, wherein the third heat exchanger performs heat exchange between the non-azeotropic refrigerant mixture of gas from the refrigerant container and the non-azeotropic refrigerant mixture from the heat exchanger functioning as an evaporator. The refrigeration cycle device of Embodiment 2 may also be Fig.16 The refrigeration cycle device 200B of the second modification of the second embodiment shown in FIG. 2 does not include a third heat exchanger. The refrigeration cycle device 200B is configured from Fig. 9 The refrigeration cycle device 200 of the present invention has a configuration in which the internal heat exchanger 7 is removed and the control device 20 is replaced with a control device 20B. Other configurations are the same and therefore description thereof will not be repeated.

[0091] Fig.17 This is a Ph diagram showing the change in the state of the non-azeotropic refrigerant mixture during cooling operation. Fig.17 The states shown correspond to Fig.16 The states of the non-azeotropic mixed refrigerant in the nodes N1 to N11 are shown in FIG. Fig.10 The same, therefore, will not be repeated.

[0092] Refer to Fig.16 as well as Fig.17 In the refrigeration cycle device 200B, since heat exchange is not performed between the non-azeotropic mixed refrigerant flowing from the node N6 to the node N7 and the non-azeotropic mixed refrigerant flowing from the node N9 to the node N10, the state of the node N6 is almost the same as the state of the node N7. The process from the state of the node N10 to the state of the node N11 represents the decompression process based on the expansion valve 4C. The enthalpy of the state of the node N11 is larger than the enthalpy of the state C1. Therefore, the enthalpy of the state of the node N5 is smaller than the enthalpy of the node N11 and larger than the enthalpy of the state C1, and the node N5 is a node where the non-azeotropic mixed refrigerant in the state C1 merges with the non-azeotropic mixed refrigerant in the state N11.

[0093] Fig.18 This is a Ph diagram showing the change in the state of the non-azeotropic refrigerant mixture during the heating operation. Fig.18 The states shown correspond to Fig.16The states of the non-azeotropic mixed refrigerant in the nodes N1 to N10 and N12 are shown in FIG. Fig.12 The same, therefore, will not be repeated.

[0094] Refer to Fig.16 as well as Fig.18 , similarly to the case of cooling operation, the state of the node N6 is almost the same as the state of the node N7. The process from the state of the node N10 to the state of the node N12 represents the decompression process based on the expansion valve 4C. The enthalpy of the state of the node N12 is larger than the enthalpy of the state C2. Therefore, the enthalpy of the state of the node N2 is smaller than the enthalpy of the node N12, which is the node where the non-azeotropic mixed refrigerant in the state C2 merges with the non-azeotropic mixed refrigerant in the state of the node N12, and is larger than the enthalpy of the state C2.

[0095] Fig.19 Is used to illustrate the Fig.16 The flowchart of the control of the expansion valve 4C by the control device 20B is shown in FIG. The main routine (not shown) for performing the overall control of the refrigeration cycle device 20B is called at regular time intervals. Fig.19 Processing shown.

[0096] like Fig.19 As shown, in S221, the control device 20B determines whether the temperature gradient is greater than the threshold value δ1. When the temperature gradient is less than the threshold value δ1 (No in S221), the control device 20 causes the process to enter S222. In S222, the control device 20 closes the expansion valve 4C and returns the process to the main routine. When the temperature gradient is greater than the threshold value δ1 (Yes in S221), the control device 20B causes the process to enter S223.

[0097] In S223, the control device 20B determines whether the opening of the expansion valve 4C is less than the reference opening. When the opening of the expansion valve 4C is less than the reference opening (Yes in S223), the control device 20B causes the process to enter S224. In S224, the control device 20B sets the opening of the expansion valve 4C to the reference opening and returns the process to the main routine. When the opening of the expansion valve 4C is greater than the reference opening (No in S223), the control device 20B causes the process to return to the main routine.

[0098] In the second embodiment, a refrigeration cycle device having a flow path switching unit is described, wherein the flow path switching unit switches the flow path to which the non-azeotropic mixed refrigerant of the gas from the refrigerant container flows. The refrigeration cycle device of the second embodiment may also be, for example, Fig. 20 A refrigeration cycle device 200C according to a third variation of the second embodiment shown in FIG. Fig.21Like the refrigeration cycle apparatus 200D according to the fourth modification of the second embodiment shown in the figure, the flow path switching unit is not provided.

[0099] Fig. 20 The structure of the refrigeration cycle device 200C shown is from Fig. 9 The refrigeration cycle device 200 of the present invention has a structure in which the three-way valve 8 and the flow path connecting the three-way valve 8 and the flow path FP2 are removed and the control device 20 is replaced by a control device 20C. The other structures are the same and therefore will not be described again. In the cooling operation, the control device 20C performs Fig.13 or Fig.14 The control device 20C performs heating operation with the expansion valve 4C closed. During the heating operation, the control device 20C does not perform Fig.13 or Fig.14 Processing shown.

[0100] Fig.21 The structure of the refrigeration cycle device 200D shown is from Fig. 9 The refrigeration cycle device 200 of the present invention has a structure in which the three-way valve 8 and the flow path connecting the three-way valve 8 to the flow path FP1 are removed and the control device 20 is replaced by a control device 20D. The other structures are the same and therefore will not be described again. In the heating operation, the control device 20D performs Fig.13 or Fig.14 The control device 20D performs cooling operation with the expansion valve 4C closed. During cooling operation, the control device 20D does not perform Fig.13 or Fig.14 Processing shown.

[0101] As described above, according to the refrigeration cycle device of Embodiment 2 and Modifications 1 to 4, the GWP of the non-azeotropic refrigerant mixture can be reduced, and the performance degradation of the refrigeration cycle device using the non-azeotropic refrigerant mixture can be suppressed. In addition, according to the refrigeration cycle device of Embodiment 2 and Modifications 1 to 4, the performance degradation of the refrigeration cycle device caused by the reduction of the weight ratio of R1123 in the circulating refrigerant can be suppressed.

[0102] The embodiments and modifications disclosed this time are also intended to be implemented in appropriate combinations within the scope of non-contradiction. The embodiments and modifications disclosed this time should be considered to be illustrative rather than restrictive in all aspects. The scope of the present invention is not indicated by the above description, but by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0103] Description of Reference Numerals

[0104] 1 compressor, 2 four-way valve, 3, 6 heat exchanger, 4, 4A~4C expansion valves, 5 storage, 7 internal heat exchanger, 8 three-way valve, 8A, 8B opening and closing valves, 9A~9C, 13 temperature sensor, 10, 20, 20A~20D control device, 11 outdoor fan, 12 indoor fan, 80 flow path switching unit, 100, 100A, 100B, 200, 200A~200D refrigeration cycle device, 110, 210 outdoor unit, 120 indoor unit, FP1, FP2 flow path.

Claims

1. A refrigeration cycle device, which is a refrigeration cycle device using a non-azeotropic mixed refrigerant, wherein: have: compressor; a first heat exchanger; A first expansion valve; A second heat exchanger; a second expansion valve, the second expansion valve being connected to the second heat exchanger via a first flow path; a third expansion valve, the third expansion valve being in communication with the first flow path; a refrigerant container, the refrigerant container being in communication with the first expansion valve, the second expansion valve, and the third expansion valve; and Control device, The non-azeotropic mixed refrigerant circulates in a first circulation direction among the compressor, the first heat exchanger, the first expansion valve, and the second heat exchanger. When the third expansion valve is opened, the non-azeotropic mixed refrigerant gas in the refrigerant container is guided to the first flow path. At least a portion of the non-azeotropic mixed refrigerant flowing into the refrigerant container from the first expansion valve is vaporized in the refrigerant container. The control device opens the third expansion valve when a first difference between a second temperature of the non-azeotropic mixed refrigerant as gas in the refrigerant container and a third temperature of the non-azeotropic mixed refrigerant as liquid in the refrigerant container is greater than a first threshold value, The refrigeration cycle device further includes a third heat exchanger connected between the refrigerant container and the third expansion valve and connected between the second heat exchanger and the refrigerant container. The non-azeotropic mixed refrigerant of the gas flowing out of the refrigerant container and the non-azeotropic mixed refrigerant sucked into the compressor exchange heat in the third heat exchanger.

2. The refrigeration cycle device according to claim 1, wherein: When a second difference between the second temperature and the fourth temperature is greater than a second threshold, the control device increases the opening of the third expansion valve, and when the second difference is less than the second threshold, the control device decreases the opening of the third expansion valve. The fourth temperature is the temperature of the non-azeotropic mixed refrigerant flowing between the refrigerant container and the third expansion valve.

3. The refrigeration cycle device according to claim 1, wherein: When the first difference is smaller than the first threshold value, the control device closes the third expansion valve.

4. A refrigeration cycle device, which is a refrigeration cycle device using a non-azeotropic mixed refrigerant, wherein: have: compressor; a first heat exchanger; A first expansion valve; A second heat exchanger; a second expansion valve, the second expansion valve being connected to the second heat exchanger via a first flow path; a third expansion valve, the third expansion valve being in communication with the first flow path; as well as a refrigerant container, the refrigerant container being in communication with the first expansion valve, the second expansion valve and the third expansion valve, The non-azeotropic mixed refrigerant circulates in a first circulation direction among the compressor, the first heat exchanger, the first expansion valve, and the second heat exchanger. When the third expansion valve is opened, the non-azeotropic mixed refrigerant gas in the refrigerant container is guided to the first flow path. The refrigeration cycle device further comprises: a flow path switching valve configured to switch a circulation direction of the non-azeotropic mixed refrigerant between the first circulation direction and a second circulation direction opposite to the first circulation direction; as well as a flow path switching unit that connects the third expansion valve to the first flow path or a second flow path connecting the first expansion valve and the first heat exchanger, The flow path switching unit connects the third expansion valve to the first flow path in the first circulation direction, and connects the third expansion valve to the second flow path in the second circulation direction.

5. The refrigeration cycle device according to any one of claims 1 to 4, wherein: The non-azeotropic mixed refrigerant includes R32, CF3I and R1123, The first weight ratio of the R32 in the non-azeotropic refrigerant mixture in the sealed state in the refrigeration cycle device is 43 wt % or less, The second weight ratio of the CF3I in the non-azeotropic refrigerant mixture in the sealed state in the refrigeration cycle device is less than the first weight ratio, A third weight ratio of the R1123 in the non-azeotropic refrigerant mixture in a sealed state in the refrigeration cycle device is 14 wt % or more.

6. The refrigeration cycle device according to claim 5, wherein: The first weight ratio is 30 wt % or less.

7. The refrigeration cycle device according to any one of claims 1 to 4, wherein: The driving frequency of the compressor when the first temperature of the non-azeotropic refrigerant mixture discharged from the compressor is higher than a reference temperature is lower than the driving frequency of the compressor when the first temperature is lower than the reference temperature.

8. The refrigeration cycle device according to any one of claims 1 to 4, wherein: further comprising an air supply device for supplying air to the first heat exchanger, The air volume per unit time of the air sending device when the first temperature of the non-azeotropic refrigerant mixture discharged from the compressor is higher than a reference temperature is greater than the air volume per unit time of the air sending device when the first temperature is lower than the reference temperature.

9. The refrigeration cycle device according to any one of claims 1 to 4, wherein: The opening degree of the first expansion valve when the first temperature of the non-azeotropic refrigerant mixture discharged from the compressor is higher than a reference temperature is larger than the opening degree of the first expansion valve when the first temperature is lower than the reference temperature.

Images